Swap between file system and in-memory storage for Shrine file uploads with RSpec.

shrine_storage.rb

# This sets up both a memory store and file system store for Shrine file uploads.
# We use the memory store by default but in cases where you want to test actual
# file uploads you can enable it with `file_upload: true` on a per example basis
require "shrine/storage/memory"
require "shrine/storage/file_system"

# We use a delegator to swap out the storage dynamically
# since the storage hash is duplicated for each uploader
class Shrine::Storage::Dynamic < SimpleDelegator
  def initialize(initial, storages)
    @_storages = storages
    super(@_storages[initial])
  end

  def change_storage(key)
    __setobj__(@_storages[key])
  end
end

Shrine.storages = {
  cache: Shrine::Storage::Dynamic.new(:memory,
    memory: Shrine::Storage::Memory.new,
    file: Shrine::Storage::FileSystem.new("public", prefix: "uploads/tmp/cache")),
  store: Shrine::Storage::Dynamic.new(:memory,
    memory: Shrine::Storage::Memory.new,
    file: Shrine::Storage::FileSystem.new("public", prefix: "uploads/tmp/store"))
}

RSpec.configure do |config|
  config.before file_upload: true do
    Shrine.storages[:cache].change_storage(:file)
    Shrine.storages[:store].change_storage(:file)
  end
  config.after file_upload: true do
    Shrine.storages[:cache].change_storage(:memory)
    Shrine.storages[:store].change_storage(:memory)
  end
end